/*
* Copyright 2003-2014 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.mps.classloading;
import jetbrains.mps.smodel.SRepositoryBatchListener;
import org.jetbrains.annotations.NotNull;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.jetbrains.mps.openapi.module.SRepository;
import org.jetbrains.mps.openapi.repository.WriteActionListener;
import org.jetbrains.mps.openapi.module.event.SRepositoryEvent;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* The class is responsible for listening {@link org.jetbrains.mps.openapi.module.SRepositoryListener} events like
* moduleAdded,
* moduleRemoved,
* etc.,
* and dispatching batch (group) events to listeners.
* It listens the start and finish of write action. It starts batching events at the start of write action
* and yields the result at the end of write action.
*
* @see org.jetbrains.mps.openapi.module.ModelAccess#runWriteAction(Runnable)
*/
public class ModuleEventsDispatcher implements WriteActionListener {
private static final Logger LOG = LogManager.getLogger(ModuleEventsDispatcher.class);
private final BatchEventsProcessor myBatchEventsProcessor;
private final List<SRepositoryBatchListener> myListeners = new CopyOnWriteArrayList<SRepositoryBatchListener>();
private final SRepository myRepository;
private final AtomicBoolean myPaused = new AtomicBoolean(false);
public ModuleEventsDispatcher(@NotNull SRepository repository) {
myRepository = repository;
myBatchEventsProcessor = new BatchEventsProcessor(repository);
}
public void init() {
myBatchEventsProcessor.init();
myRepository.getModelAccess().addWriteActionListener(this);
}
public void dispose() {
myRepository.getModelAccess().removeWriteActionListener(this);
myBatchEventsProcessor.dispose();
}
public void pause() {
myPaused.compareAndSet(false, true);
}
public void proceed() {
myPaused.set(false);
}
@Override
public void actionStarted() {
myBatchEventsProcessor.startBatching();
}
@Override
public void actionFinished() {
try {
if (myPaused.get()) {
return;
}
List<SRepositoryEvent> batchedEvents;
do {
batchedEvents = myBatchEventsProcessor.flush();
if (!batchedEvents.isEmpty()) {
fireModuleEvents(batchedEvents);
}
} while (!batchedEvents.isEmpty());
} finally {
myBatchEventsProcessor.finishBatching();
}
}
public boolean flush() {
if (myPaused.get()) {
return false;
}
final List<SRepositoryEvent> batchedEvents = myBatchEventsProcessor.flush();
if (batchedEvents.isEmpty()) return false;
myRepository.getModelAccess().checkWriteAccess();
fireModuleEvents(batchedEvents);
return true;
}
public final void addRepositoryBatchEventsListener(SRepositoryBatchListener listener) {
myListeners.add(listener);
}
public final void removeRepositoryBatchEventsListener(SRepositoryBatchListener listener) {
myListeners.remove(listener);
}
private void fireModuleEvents(List<SRepositoryEvent> events) {
myRepository.getModelAccess().checkWriteAccess();
for (SRepositoryBatchListener listener : myListeners) {
listener.eventsHappened(events);
}
}
}